Some Meteorite Realities

Nearly all of the photos in the links below were sent to me by persons inquiring whether the object in the photo was a meteorite. The links give more details and contain photos related to the point I am stating.

1. JUST THE FACTS

 

Most rocks are not meteorites

  • I am sent photos of dozens of meteorwrongs every day.
  • Think of it this way: If you see it driving down the freeway and it has 4 wheels, 2 headlights, and a trunk, then it is probably an automobile, not an alien spacecraft.

 

The chance of finding a meteorite is exceedingly small

  • Since 1900, about 1800 meteorites have been found in North America. That is about 15 per year. About two thirds of meteorites found in the United States have been found in arid regions of California, Nevada, Arizona, New Mexico, Texas, and Kansas.
  • Even experienced meteorite hunters can go for years between finds.
  • Some statistics

 

The chance of finding a meteorite that has just fallen is even smaller

  • Since 1900, the numbers of recognized meteorite “falls” is about 814 for the whole Earth. That is 6.7 per year. Only 137 of those occurred in North America. That is 1.1 per year. Even when a meteorite is observed to fall, experienced meteorite hunters may find only a few stones when hunting dawn to dusk for a week.

 

The chance of finding a lunar or martian meteorite is even smaller

  • Only about 7 in 1000 meteorites is from the Moon and 5 in 1000 is from Mars. No lunar meteorite has yet been found in North America, South America, or Europe.

 

If there is no fusion crust, then neither you nor I can identify a rock as an achondrite just “by looking” at it

  • achondrites
  • Achondrites look like terrestrial rocks. It requires sophisticated chemical or mineralogical tests to distinguish a rock as an achondrite and to identify just what type of achondrite the rock is.

 

If you found a rock, it might be a meteorite, but it is definitely not a meteor

  • meteor
  • You cannot hold a meteor in your hand.

 

If you saw a meteor and then found a stone, then the stone is not a meteorite

  • meteor
  • Meteorite fragments land far from where you last saw the meteor and there is no way that observers at a single point on the Earth’s surface are going to find fragments of the meteorite. It requirwes triangulation from several viewpoints, usually with cameras.

 

Not everything that falls from the sky is a meteorite

  • thud
  • Most rocks that fall from the sky are not meteorites.

 

Not every rock that “looks like” a meteorite is actually a meteorite

  • “It looks just like a meteorite.”
  • It is often not possible to determine whether a rock is a meteorite just from its appearance, particularly in a photograph. Achondrites such as meteorites from asteroids, Moon, and Mars can look very much like some types of common earth rocks.  There is no polite way to say this – most people who contact me saying, “It looks like a meteorite to me” do not know what to look for.

 

Some meteorites do not look like meteorites

  • Kalahari 009
  • If someone had walked into my office with this rock, I would have said that it was not a meteorite.

2. FUSION CRUST & REGMAGLYPTS

 

If it does not have a fusion crust, then it is probably not a meteorite

 

“Maybe the fusion crust got worn off”

  • no fusion crust
  • If a rock does not have a fusion crust, then there is no reason to suspect that it is a meteorite no matter how many other meteorite-like features it may have. Put another way, if she is wearing a pretty dress and playing a grand piano on a stage with a symphony orchestra behind her, then she is probably a concert pianist. If she is jogging down the beach with her dog, then she might be a concert pianist, but probably not. How can you or I tell?

 

If it has some kind of rind, coating, or crust, then the rind, coating, or crust is probably not a meteorite fusion crust and the rock is not a meteorite

  • rinds, coatings, & crusts
  • There are numerous processes on Earth that cause rocks to have rinds, coatings, and crusts. Some of these, particularly desert varnish, can look remarkably like a meteorite fusion crust.

 

If it has a thick rind or coating, then it is not a meteorite

  • too thick
  • Fusion crusts are thin because as soon as the exterior of the meteorite melts, the liquid is sloughed off due to of the high velocity of travel of the meteoroid through the atmosphere. The fusion crust does not build up, except perhaps on the trailing side. Meteorite fusion crusts are rarely more that 1-2 mm thick.

 

If the inside of the rock is the same color and shade as the outside, then it is probably not a meteorite

  • inside-outside
  • Fusion crusts are usually darker than the interior of a meteorite. Most fusion crusts are dark; those on some achondrites may be light colored.

 

Black, shiny surfaces are not necessarily meteorite fusion crusts

  • polished rocks
  • Some dark, fine-grained-crystalline earth rocks can be rounded and polished by abrasion to the point where the surfaces become shiny like a meteorite fusion crust. Such rocks, however, are these same color and shade on the inside as the outside, unlike for a meteorite.

 

If it is big and it does not have regmaglypts, then it is probably not a meteorite

  • regmaglypts
  • Not all meteorites have regmaglypts but big ones usually do. If it does not have a fusion crust, then it does not have regmaglypts.

 

Not all dimples are meteorite regmaglypts

  • regmaglypts NOT
  • There are many terrestrial processes that lead to regmaglypt-like depressions in rocks.

 

Just because a rock has “flow lines” does not mean that it is a meteorite

  • flow lines
  • Most meteorites do not have “flow lines.” There are terrestrial processes that lead to flow-like features on the surface of some rocks. If it does not have a fusion crust, then it does not have meteorite flow lines.

3. MAGNETIC ATTRACTION AND METAL

 

If a rock does not rather strongly attract a cheap ceramic magnet, then it is probably not a meteorite

  • magnetic attraction | metal, iron, & nickel
  • About 95% of meteorites will attract a cheap magnet.
  • Do not use a rare-earth (neodymium) magnet to test for magnetic attraction. A meteorite will attract a cheap ceramic (“refrigerator”) magnet or a compass. A rare-earth magnet will attract many terrestrial rocks.

 

If a rock attracts a cheap magnet but you cannot see shiny metal grains on a sawn or broken surface, then the rock is not a meteorite

 

If a rock contains shiny things that look like metal, but the rock does not attract a magnet, then the shiny things are probably not metal and the rock is not a meteorite

  • metal, iron, & nickel
  • Some sulfide and oxide minerals look like metal. Micas are often shiny. The presence of shiny specks does not necessarily mean the rock contains metal.

 

If a rock does not attract a cheap magnet, then it could still be a meteorite, but it is probably not

  • metal, iron, & nickel
  • Some of the rarest types of meteorites, the achondrites, do not attract magnets for the same reason that most earth rocks do not attract magnets – they do not contain magnetite or iron-nickel metal. Achondrites are rare, however. Only 2.5% of the ~1500 stony meteorites that have been found in the U.S. are achondrites.

 

If the “rock” looks metallic but does not strongly attract a cheap magnet, then it is not a meteorite

  • looks shiny and metallic
  • I have been sent chunks of silicon, aluminum, ferromanganese, chromium, and other industrial metals. Any metal that you can see in a meteorite will attract a magnet.

 

If it is metallic and attracts a magnet, then it might be an iron meteorite, but it is probably not

  • man-made metal things
  • Humans have been making and losing metal things for thousands of years. If it looks like metal and attracts a magnet, then you have to have it analyzed for iron, nickel, manganese, and chromium to determine whether it is man-made or an iron meteorite. If it is metallic but does not attract a magnet, then it is not a meteorite.

 

If it looks metallic and you can bend it or break it, then it is not a meteorite

  • Iron meteorites do not break unless they are badly rusted.

 

If your metal detector says that the rock contains nickel, then it is lying

  • no metal detectors
  • Metal detectors are not that smart. They might be able to tell U.S. nickels from pennies, but they cannot tell if iron metal contains enough nickel metal to be a meteorite.

4. BULK PROPERTIES AND SHAPE

 

If a rock is “heavy for its size,” then it might be a meteorite, but it is probably not

 

If a rock is not heavy for its size, then it might be meteorite, but it is probably not

  • density & specific gravity
  • Some rare meteorites, achondrites that do not contain metal, have low densities like common earth rocks. Density is not all that useful for distinguishing meteorites from meteorwrongs.

 

If a rock consists mostly of hematite, magnetite, or some other iron oxide, then it is not a meteorite

  • iron oxide concretions
  • Iron-oxide nodules or concretions are the most common kind of meteorwrong sent to us. Highly weathered meteorites may contain some hematite, magnetite, and maghemite. Do a streak test.

 

If it is a big rock, then it is not a meteorite

  • too big
  • Most stony meteorites are smaller than people think they are. If you like statistics, see this. Also, see this for the masses of the >70 individual stones that have been found from the recent fall of the Sutter’s Mill meteorite in California. Iron meteorites can be big, however: Willamette | XinJiang | Campo del Cielo | Hoba

 

If a rock is “really hard,” then it is probably not a meteorite

  • hard
  • Because meteorites do not contain quartz, the hardest common terrestrial mineral, they are not very hard. An ordinary chondrite can easily be smashed with a hammer.

 

If it is spherical or circular, then it is probably not a meteorite

  • spheres
  • There are processes on Earth that lead to spherical rocks. These processes do not occur where most meteorites come from. Here is a photo of the only exception of which I am aware: Canyon Diablo spherules

 

If it is square, rectangular, hexagonal, or has flat or parallel sides, then it is probably not a meteorite

 

If it is highly oblate (flat and thin), then it is not a meteorite

  • too oblate
  • Except for Frisbees and flying saucers, oblate objects are not all that aerodynamically stable and would be break apart during the descent through the atmosphere.

 

If it is long and thin, then it is not a meteorite

  • long and thin
  • A rock or piece of metal with a high aspect ratio (length-to-width) is not aerodynamically stable and would break apart in the atmosphere.

 

If a rock is a glacial or river cobble, then it is not a meteorite

  • cobble
  • Glacial cobbles are common on Earth and they do not have fusion crusts.

 

If it is hollow, then it is not a meteorite

  • hollow
  • Meteorites are not hollow.

 

If it is glass, glassy, or has conchoidal fractures, then it is not a meteorite

  • glass
  • Some meteorites contain some glass, but none are solid glass.

 

If it looks like a potato or some other vegetable, then it is not a meteorite

 

If it looks like a brain, then it is not a meteorite

  • brain
  • It is just a terrestrial sedimentary rock.

 

If it is stony (not iron) and has a really goofy, weird, or bizarre shape, then it is not a meteorite

  • goofy
  • Stony meteorites do not look have goofy shapes.

 

If you found a rock that was hot to touch or appears to have been subjected to “extreme heat,” then it is not a meteorite

  • hot rock
  • Meteorites do not land “hot.”

 

If it is radioactive, then it is not a meteorite

  • radioactive
  • Meteorites are less radioactive than are most earth rocks. The only meteorite of which I am aware to actually register on a Geiger counter is lunar meteorite Sayh al Uhaymir 169, which has 600-700 times the abundances of thorium and uranium than an ordinary chondrite.

5. EXTERIOR

 

If it is stony (not an iron) and has a rough exterior, then it is probably not a meteorite

  • rough
  • For small meteoroids, 90% of the mass is lost to ablation as they come through the Earth’s atmosphere. Rough surfaces do not survive the process – they are smoothed and rounded.

 

If it is angular, with sharp edges or points and no smooth sides, then it is probably not a meteorite

  • angles and edges
  • For small meteoroids, 90% of the mass is lost to ablation as they come through the Earth’s atmosphere. Edges and “corners” are the first parts to ablate away. Put an ice cube in water and wait for 90% to melt. The “cube” that is left will have no edges or points. It is like that with meteorites.

 

If it is stony (not iron) and has protuberances, then it is probably not a meteorite

  • protuberances
  • For small meteoroids, 90% of the mass is lost to ablation as they come through the Earth’s atmosphere. Any parts that stick out from the surface are the first parts to ablate away. Put an ice cube in water and wait for 90% to melt. The “cube” that is left will have no stick-out parts. It is like that with meteorites.

 

If it has “craters” on the surface, they are not impact craters and the rock is not a meteorite

  • asteroids and meteoroids
  • Asteroids have craters, meteorites do not. The surface material ablates away as the meteorite comes through the atmosphere, erasing any craters the meteoroid may have had.

 

If a rock “looks burned,” it is probably not a meteorite

  • burned
  • Meteorites do not burn. Meteorites are not burned. The outside has melted, but they have not burned and they do not “look burned.”

 

If it has internal swirls or coarse surface flow features, then it is not a meteorite

  • swirls and flow features
  • Although there may be processes in space that can lead to such rocks, we have not seen meteorites like this yet.

 

If a rock has a pattern that radiates from the center, then it is not a meteorite

  • radiating pattern
  • Although there may be processes in space that can lead to such rocks, we have not seen meteorites like this yet.

 

If a rock has concentric features, then it is not a meteorite

  • concentric rings
  • Although there may be processes in space that can lead to such rocks, we have not seen meteorites like this yet.

 

If a rock has layers, laminations, or any kind of planar or parallel linear features, then it is definitely not a meteorite

  • layers and stripes
  • 99+% of meteorites come from asteroids that are too small to have any appreciable gravity. If there is no gravity, then there is no way to form layers. Here is the only exception I know about, and it is a terrestrial weathering effect.

 

If it has veins, particularly ones that stick out or appear to be planar, then it is not a meteorite

  • veins
  • Melt veins are seen in some meteorites, but they are never highly linear. Rarely, there might be veins of impact melt (see NWA 5744 and Harper Dry Lake 036). Some others have veins of metal. Many of the veins in meteorwrongs are fractures that have filled with quartz. Quartz-filled fractures are common in earth rocks but are not seen in meteorites.

 

If it has fractures or filled fractures, then it is probably not a meteorite

  • fractures
  • If a meteoroid is fractured, then it will break apart along the fractures from the stress of passing through the atmosphere. Ordinary chondrites that have been on or in the Earth a long time will self fracture as they metal rusts, but they will look rusty. (See story and photo of the Lake House chondrite, for example.)

 

If it is whitish on the outside, then it is not a meteorite

  • too white
  • Most meteorites are shades of grays and browns; some may be rusty-reddish on the outside. They are never whitish.

 

If there is writing or a picture on it, then it is not a meteorite

  • picture
  • Meteorites do not fall out of the sky with writing or pictures on them. If you have or find a rock with writing or pictures, then it is probably not a meteorite.

 

If there is a face on it, then it is not a meteorite

  • face
  • If you find a rock with a face on it, then it is not a meteorite.

6. INTERIOR

 

If it has a lot of vesicles (gas bubbles, holes) in it, then it is not a meteorite

  • vesicles & amygdules | more vesicles
  • Very few stony meteorites have vesicles or holes. In those that do, the holes are sparse and small. Vesicles require gas and that the rock was once molten. Most meteorites were never molten. Iron meteorites sometimes have holes, however.

 

If it is glassy and vesicular, then it is not a meteorite

 

If it contains lots of amygdules, then it is probably not a meteorite

 

If it is stony and has large holes in it, then it is not a meteorite

 

If a rock contains elongated minerals or clasts, then it is probably not a meteorite

  • needles
  • It is rare for the aspect ratio of a clast or large mineral in a meteorite to exceed 3-to-1.

 

If a rock has clasts or minerals grains with square, rectangular, or parallelogram shapes, then it is probably not a meteorite

  • geometric
  • Geometric shapes happen in terrestrial rocks, but the minerals that cause this are rare in meteorites.

 

If a rock contains round things, the round things are not necessarily chondrules

 

If a rock contains obvious quartz, then it is not a meteorite

  • quartz
  • Quartz is the only common mineral that will easily scratch glass. Try to scratch glass with a sharp edge of the rock. If it makes a deep scratch, it is not a meteorite.. Quartz is rare in meteorites and is microscopic in size.

 

If it looks metallic and is shiny on the outside, then it is not a meteorite

  • shiny
  • Some sulfide and oxide minerals look metallic and some non-ferrous metals are shiny.

 

If it contains fossils, then it is not a meteorite

  • no fossils
  • If a rock contains fossils, then it is not a meteorite. Fossils occur in earth rocks because there is life on Earth. Thus far, we do not have evidence of life on any of the places where meteorites come from, so if it has fossils, it is an earth rock. If we ever find a meteorite that contain fossil life forms, that would be a big deal, but the burden of proof would be very heavy.

 

If it is reddish, violet, blue, green, yellow, or orange particularly on the inside, then it is probably not a meteorite

 

If it is transparent or translucent, it is not a meteorite

  • transparent
  • So far, no one has found a transparent meteorite.

 

Just because a rock “looks like” a planetary impact breccia does not mean that it is a meteorite or a Moon rock


7. WHERE DID YOU FIND IT?

 

If it does not look like other rocks in the vicinity, then it might be a meteorite, but it is probably not

  • rocks move
  • Glaciers, moving water and wind, and (most importantly) humans have moved, dropped, and placed a lot of unusual rocks far from where they came from.

 

If you found it on a beach, then it is not a meteorite

  • beach
  • I am aware of only two meteorites, Southampton (pallasite) and Penouille (iron) that were found on a beach. Both are rich in iron metal. If a stony meteorite landed in the water and later washed up on a beach it would have lost its fusion crust as a result of abrasion by wave action. If it were an ordinary chondrite, it would likely have broken apart from rusting of the iron metal. If it survived as a rock, it would be all but impossible to identify as a meteorite just “by looking.” It would not look at all special, except maybe for some rusty spots. But who knows?  Nobody has ever found and recognized a stony meteorite on a beach!

 

If you found it in a stream bed, along a river, or any other place where there are lots of rocks, then it is almost certainly not a meteorite

  • stream
  • With 2 exceptions that occur to me, successful meteorite hunters search for meteorites in places where there are not a lot of rocks. If you want to find your car easily, park it in an empty parking lot.

 

If you found a rock near a road or railroad track, then it is not a meteorite

  • railroad
  • It may have fallen off a train or truck.

 

If it is in a conspicuous place, then it is not a meteorite

 

If you found a lot of rocks in one place, then none of them are not meteorites

  • too many rocks
  • Meteorites break apart in the atmosphere 10 miles or more above the Earth’s surface. The fragments are spread out over miles (strewn field). The chance that 2 or more land within seeing distance of each other is very small.

 

If you found a rock in a “crater,” then it is not a meteorite

  • not a crater
  • There are several geologic (karst, glacial kettle), as well as anthropogenic (man-made), processes that make circular depressions in the ground. Meteorites hit the ground at terminal velocity, about 200-400 miles per hour. That is not fast enough to make a crater unless the rock is large (>meter size? I really do not know).

 

If it has been in your family for years, then it is probably not a meteorite


8. SELLING & BUYING METEORITES

 

Many-to-most rocks sold over the Internet as meteorites really are meteorites, but some are not

  • rocks that do not look like lunar meteorites to me | caveat emptor
  • There are many reputable meteorite dealers that sell real meteorites on the internet. I have bought several meteorite specimens from such dealers.
  • There are foolish and devious people who try to sell backyard rocks as meteorites. Advertisements for alleged meteorites that are filled with meaningless, pseudoscientific mumbo-jumbo and absurdly high prices are usually selling just rocks, Most rocks offered on e-bay for prices >$10,000 are not really meteorites. Sometimes you can buy a cheap meteorwrong, however, but it is even cheaper to go find your own.

 

If you find a real meteorite, it is not worth as much ($) as you think or wish

  • cheap
  • There are several factors that affect the price of a meteorite: rarity of the type of meteorite, how big or small it is, intrinsic attractiveness, whether it is a fall or a find, and whether there is a good story to go with it.

9. FINAL WORDS

 

Meteorology is not the same as meteoritics

In English, there is only one way to spell meteorite

  • I have received e-mails with meteorite spelled many different ways:
  • météorite, mateorite, mateorito, matreot,  matronite, meadorite, meatioright, meator, meatorite, medeiorite, medeorite, mederite, mederoite, mediroit, medorite, medrolite, meeorite, meetyouwrite, mentor, mentor rite, meorite, meoteorite, meotorite, meroite, mereorite, merteorite, met5eorite, metaroide, mete, meteeor, meteiorate, meteiorrite, meteiright, meteirite, metemorite, météo, meteoiarte, meteoite, meteorait, meteorete, meteori, meteoric, meteorid, meteoride, meteorie, meteoriet, meteorilite, meteoriote, meteorit, météorite, meteorith, meteorito, meteoritote, meteoritre, meteoritt, meteoritte, meteormu, meteoro, meteorolite, meteorprite, meteortie, meteory, meteoryt, meteoryty,  meteotite, meteprite, meter, meteright, meteriod, meteriorite, meteriot, meteriote, meterite, metermortie, meteroide, meteroit, meteroite, meteror, meterorite, meterote, meterotie, meteroyty, meterrite, meterrite, metetro, meteurite, metheorite, metior, metioreit, metioret, metiorit metiorite, metoerite, metor, metoor, metorie, metorit, metorite, metortie, metoroite, metreot, metrio, metriote, metrite, métrite, metro, metroit, metroite, metrorite, metterrite, meturate, metworite, maturate, miderorite, miteorete, miteorite, moteor, motoit, mrtrorite, & mteorite

Suggested by Martin (an expert): “If an expert tells you that your rock is not meteorite, then: Believe him!”

  • Or, seek the advice of another expert. But be aware – all meteorite experts I know are so deluged with questions by wannabe meteorite finders that most will likely not reply.
  • I get contacted about 20 times a day. So, I do not have time to chat with you and I have no interest in arguing with you if you do not agree with my free opinions. I am retired. If you do not like my response, contact someone else.

Corollary: If an “expert” tells you that your rock IS a meteorite, then seek another opinion

  • Expert says: “Yup, that is a meteorite for sure.” How many real meteorites has the expert actually seen?
  • Most “experts” at local colleges, universities, and museums are experts on something else.

A critic of an earlier version of this page said, “Your definitions of meteorites are not always the same as other Scientists or Geologists, someone in your profession is Wrong!!!!!” True, in part. On the other hand, Winston Churchill is alleged to have said (about something completely different), “There are a terrible lot of lies going around the world, and the worst of it is half of them are true.” Compromise: I admit that all of these statements are untrue some of the time. Also, these are not “definitions;” they are just guidelines.